FTTH (Fiber To The Home), which is the installation of fiber optic cables in homes and companies to enable high-speed communication, has emerged in recent years. The communication costs of FTTH are fairly lower than other communication means that enable continuous connections and its transmission speed is remarkably fast. However, the installation of FTTH involves the installation of new communication lines, which hinders the widespread use of FTTH. For example, installing FTTH in an apartment requires the use of common spaces in the apartment. Accordingly, even if only one of the households in an apartment wants to install FTTH, the installation requires the approval of the board of co-op or the like that manages the apartment. Furthermore, installing FTTH in some high-rise apartments can be technically difficult.
On the other hand, with the recent improvements in semiconductor technology and development of new algorithms, faster Power Line Communication (PLC) that uses frequencies in the range between 20 to 30 MHz is nearing commercial use as described in “High-Speed Power Line Communication System Overview” (High-Speed Power Line Communication Alliance of Japan, Dec. 16, 2004). PLC can use existing power lines without modifications and therefore does not require installation of new communication lines. FTTH can be installed considerably readily compared with FTTH or even cable television or ADSL (Asymmetric Digital Subscriber Line), and is expected to be widely used in general households.